We are waiting for the new START treaty to be signed in the "Spanish Room" at Prague Castle. The best fact so far: Mick Jagger donated the remote control dimmer system for the lights.

Obama and Medvedev are about to walk in

UPDATE The treaty has been signed, and both presidents have spoken. Obama was far more upbeat about future arms control negotiations. Medvedev was more prosaic and presented missile defence as a continuing problem. More soon..

New strategic arms reduction treaty (Start) being signed by US president and his Russian counterpart, Dmitry Medvedev, will shrink each nation's arsenal of strategic nuclear warheads to 1,550 over seven years – about two-thirds of the 2,200 currently permitted